Plaid for DNS and custom domains-as-a-service (dnspassport.com)

If you’ve ever wanted to give your customers custom domains, send email on their behalf or manage their DNS records, would love feedback on dnspassport.com. Built this out for my current company and thinking of spinning this infrastructure out.

What does this do that you can't do by integrating with AWS's or another registrar's API?

I'm not sure I understand this.